Field of the Invention
The present invention relates to sheet post-processing devices and image forming devices, and specifically to techniques for stably ejecting a sheet that is long in a feed direction (FD).
Related Art
Among image forming devices such as photocopiers are in-body paper ejection types in which a printer is disposed in a space (hereafter, “in-body space”) below a scanner and a recording sheet on which an image is formed by the printer is temporarily ejected into the in-body space.
Among in-body paper ejection types of image forming devices, a configuration may be considered in which recording sheets ejected into the in-body space are stacked into a recording sheet stack and pushed to a device front tray (hereafter, “front tray”). By adopting such a configuration, width of an image forming device can be decreased.
However, in a case in which an image forming device forms images by using recording sheets of various sizes, when a push-out member that is short in FD length is used to push a recording sheet stack that is long in FD length (hereafter, a “long sheet stack”) to the front tray, it can occur that the long sheet stack rotates and cannot be cleanly pushed out to the front tray.
If the push-out member is made longer in response to such a problem, a high mechanical strength becomes required for the push-out member, leading to an increase in component cost. Further, an image forming device directed to space saving usually does not have much leeway in terms of space, and therefore location of the push-out member is limited and increasing length of the push-out member may not be possible.
Further, in order to drive a long push-out member a powerful drive source is required, but such a drive source has a problem of high power consumption. When a long push-out member is used, power consumption is also high when a recording sheet stack having a short length is pushed out, consuming unnecessary power in a way that is contrary to power saving requirements.